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S80 '06-'16 / V70 & XC70 '07-'16 General Forum for the P3-platform S80 and 70-series models |
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Brake pedal sinking when engine onViews : 762 Replies : 4Users Viewing This Thread : |
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#1 |
Member
Last Online: Yesterday 14:54
Join Date: Aug 2021
Location: Lancashire
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2010 XC70 D5
Bled the brakes all the way around twice. First time used a vacuum bleeder and the second time did it Ye Old fashioned way When engine is off, brake pedal feels solid When you start the engine and press the brake, the pedal bites normally as expected, then sinks. My first thought was a bad internal seal on the master cylinder. However, I went into VIDA and pulled up both the "Brake Pedal Travel" and "Brake Pressure" Now I can't remember the exact values but when you press the brake, lets say it bites at 8mm travel, and goes to 80psi pressure, then the pedal will sink down to lets say 13mm, but the pressure stays at 80psi the whole time, so it's not leaking off. In act, I held the pedal for as long as I could stand and the pressure never decreases. I went into the BCM in VIDA and operated all the valves and ran the ABS motor to see if there was maybe some trapped air I could free up, but that didn't seem to change anything. Any ideas? Thanks everyone ![]() |
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#2 |
Premier Member
Last Online: Jun 17th, 2024 18:49
Join Date: Dec 2002
Location: Renfrewshire
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I think you may be suffering from brake pedal creep?
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Tek-Emo Villis Emo Bis V70 SE NAV 1.6 D2 2015MY POWERSHIFT, D4162T, 93000miles, RED. /VOL FCR/PEPER OBD2/Acron 9135 OBD2/L.E.D Flasher/VDASH/ANCEL BA301/Topdon Top Scan |
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#3 |
Premier Member
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This is normal for this kind of brake system.
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#4 |
Junior Member
Last Online: Sep 10th, 2022 14:42
Join Date: Oct 2017
Location: CHESTER LE STREET
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#5 |
Premier Member
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Some of these active systems go all the way to the floor without being broken.
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